Tube-ice machine using compressor to reverse pressure



July'6, '1948. B. F. KUBAUGH 2,444,514

TUBE-ICE MACHINE USING COMPRESSOR T0 REVERSE PRESSURE Filed Jan. 28,1944 2 Sheets-Sheet 1 .5. .F' liubauy (Value I?) 25' (Value 6) y 6,1948- a. F. KUBAUGH 2,444,514

4 TUBE-ICE MACHINE USING COMPRESSOR TO REVERSE PRESSURE Filed Jan. 28,1944 2 Sheets-Sheet 2 7 l9 8 l 14 [I I 27 0 /a 28 I as 00 ,6

a 33 30 m U 2 F3 35 m /d' 34 f r F l Condenser fvaporafsir Compressor3mm .BI Kubauyfz Patented July '6, 1948 TUBE-ICE MACH IN E USINGCOMPRESSOR TO REVERSE PRESSURE Benjamin F. Kubaugh, Louisville, Ky.,assignor to Henry Vogt Machine Co. Inc., Louisville, Ky., acorporationof Kentucky Application January 28, 1944, Serial No. 520,086

9 Claims. (Cl. 62-3) This invention relates to the manufacture of ice byfreezing water in a vessel in the evaporator chamber of a Carnot typerefrigeration system, in which the ice is thawed from adherence to thewalls of the vessel by the substitution of hot gaseous refrigerant inthe evaporator chamber for the liquid refrigerant which has effected thefreezing.

This method of thawing has been practiced in the tube ice machineforming the subject of Kubaugh Patent No. 2,200,424, granted May 14,1940, and Kubaugh Patent No. 2,239,234, granted April 22, 1941, in whichice is periodically frozen in an upright bundle of open ended tubesextending through the shell of the evaporator, the ice being thawed fromthe inner walls of the tubes following the freezing period. Since theliquid refrigerant in the evaporator chamber is at relatively lowpressure while hot gaseous refrigerant is available in the condenser atrelatively high pressure, the system described in said patents employsthe hot gas from the condenser to displace the liquid refrigerant fromthe evaporator temporarily, it being collected in a displacementreservoir and re-admitted to the evaporator at the end of the evacuationcycle for the next freezing period.

In practice it was found that the volume of gas in the condenser was sosmall that when its pressure became equalized with that in theevaporator, the resultin pressure was insufficient to completelydisplace the liquid refrigerant so that it was necessary during thefreezin period to divert a part of the hot compressed gas from the highside of the compressor to an auxiliary storage reservoir to supplementthe volume of hot gas from the condenser. This expedient resulted inless than the maximum of refrigerant re-liquefied in the condenser.

Then too, the mixing of the relatively small volume of condenser gaswith the cold gas in the evaporator unduly lowered the thawingtemperature of the mixture, while the gas in the storage reservoir hadan opportunity to cool somewhat, so that the thawing effect was slowerthan it might have been under optimum conditions.

Since it was, of course, necessary to cut off the low side of thecompressor from the evaporator at the end of the freezing phase andprior to the evacuation phase, the compressor during the evacuationperiod was drawing in nothing, therefore compressing nothing, butoperating at a high vacuum and constituting a useless load upon thesystem.

The present invention has for its principal ebject to provide an icemaking system of the type described, in which at the end of the freezingperiod, the suction side of the compressor is switched from theevaporator to the condenser and the pressure side of the compressorswitched from the condenser to the evaporator. By this reversal of theobjective functioning of the compressor, it on the one hand, delivershot compressed gas to the evaporator in sufficient volume and underadequate pressure to displace the liquid refrigerant therefrom, thusavoiding the need for any auxiliary storage reservoir, and'on the otherhand, it does useful refrigeration work upon the condenser andassociated receiver, lowering the temperature of the liquid refrigerantsupplied to the evaporator.

Other objects of the invention will appear as the following descriptionof preferred and practical embodiments thereof proceeds.

In the drawings which accompany and form a part of the followingspecification, and throughout the several figures of which the samereference characters have been used to denote identical parts:

Figure 1 is a. view in side elevation, largely diagrammatic, showing asimple form of ice making system embodying the principle of the subjectinvention;

Figure 2 is a diagrammatic view showing the controller which operatesthe valves;

Figure 3 is a view similar to Figure 1, showing a system in whichreversal of the objective compressor functions is automaticallyresponsive to pressure changes in the system;

Figure 4 is a conventionalized diagram illustrating the broad principlesof the invention.

Referring first to that form of the invention shown in Figure 1, therefrigeration system is of the Carnot type, including the compressor lwhich normally sucks from the upper part of the evaporator shell 2 anddelivers hot compressed gaseous refrigerant to a condenser unitcomprising the condenser 3, in which it is liquelied and a receiver 4 inwhich the condensed refrigerant is collected and from which the liquidrefrigerant is supplied to the evaporator according to refrigerationneeds.

The reference character 5 represents the low pressure conduit from theevaporator to the low side of the compressor, having a cut-off valve 6,and communicating with the evaporator by way of a liquid trap l. Thereference character 8 represents a conduit from the high pressure sideof the compressor to the condenser, and 9, a conduit from the receiverto the evaporator com- 3 municating with the latter through a liquidlevel maintaining device Ill.

Inthe illustrated embodiment of the invention, the evaporator shell 2contains a plurality of vertical tubes open at both ends, the upper endscommunicating with a water chamber l2, the lower ends extending throughthe bottom of the shell. Water from the chamber l2 flows through thetubes 5 and congeals upon the inner walls of said tubes, formingcylinders of ice the thickness of walls of which dependsupon the lengthof the freezing period. In order to thaw the ice cylinders from theiradherence to the walls of the tubes II, the liquid refrigerant in theshell is displaced by hot gaseous refrigerant derived from the system. Adisplacement reservoir I4 is therefore provided, to which the liquidrefrigerant is temporarily transferred through a conduit |'5communicating with the lower part of the shell. A branch conduit l6 forhot gas connects the upper part of the shell with the conduit 8, and hasthe cut-off valve l1.

It will be understood that the subject invention is not necessarilyconcerned with the specific tube ice freezing machine above described,but that any water containing vessel within the evaporator in which iceis frozen and from adherence to the walls of which it is thawed by hotrefrigerant gas to effect its discharge from said vessel, is within thepurview of the invention.

The system as described thus far, is old, and in order to distinguishthe new from the old, a brief description of the operation of the knownsystem will now be given. At the end of the freezing period the valve 6is closed, cutting off the low side of the compressor from theevaporator. The compressor continues tooperate, drawing a high vacuumbut compressing nothing, and constituting a useless load on the power bywhich the compressor is driven. The valve i1 is also opened at the endof the freezing period, putting the condenser into communication withthe shell. Since the suction gas in the evaporator is-at a much lowerpressure than the hot compressed gas in the condenser, an equalizationof pressure occurs, but the volume of compressed gas in the condenser isso inconsiderable that the resulting equalized pressure is generallyinsufficient to completely evacuate the liquid refrigerant from theshell,

.so that resort was had to the provision of an auxiliary storagereservoir, not shown into which some of the compressed gas from the highside of the compressor was diverted during the freezing period andadmitted to the shell for evacuation purposes concurrently with theadmission of the gas from the condenser.

The disadvantages of this arrangement are not only that the compressoris a useless load on the system during the evacuation period, but thatthe auxiliary storage reservoir is objectionable as oocupyingunnecessary space, and the storage of some of the gas delivered by thehigh side of the compressor robs the condenser and results in lessrefrigerant being liquefied in the condenser. Furthermore, the gasstored in the auxiliary reservoir cools somewhat, and the gas from boththe condenser and storage reservoir cools considerably in expanding, sothat while the gas employed for evacuation is still warm enough to meltice, its thawing effect is more sluggish than if it did not suffer theseheat losses.

The subject invention adds to the known system the followinginstrumentalities: a relief conduit ill from the top of the displacementreservoir ll to the suction conduit 5, having a cut-off valve 20; avalve 2| in the conduit 8 for cutting off the high side of thecompressor from the condenser, and a conduit 22 between the condenserconduit 8 and the suction conduit 5,. by-passing the valve 2| forplaclng the condenser in communication with the low side of thecompressor and provided with a cut-oil valve 23. The operation of thesystem during the evacuation phase may be regarded as two stages, firsta pressure equalizing stage which takes place immediately at the end ofthe freezing period, and second, the evacuation stage.

At the end of the freezing period the valve 6 is closed; the valves l1and 20 are opened, the valve 2| remaining open, and the valve 23remaining closed. Closing of the valve 6 terminates the freezing period.Opening of the valve 20 causes the compressor to draw on thedisplacement reservoir M, to make room for the liquid refrigerant to bedisplaced from the shell 2. Opening of the valve |1 places the condenserinto communication with the evaporator and equalizes the gas pressure inthe condenser and evaporator.

After a few seconds, which may be termed the pressure equalizationperiod, the valve 2| is closed and the valve 23 opened. The compressornow draws gas from the condenser and receiver by way of the conduits 8and 22, and delivers it compressed and heated to the evaporator 2 by wayof the conduit Hi.

There is an unlimited volume of gas available in the condenser, for asthe pressure on the surface of the liquid diminishes, the rate ofevaporation of the liquid accelerates. This also cools the liquidrefrigerant in the receiver so that the liquid refrigerant is suppliedto the evaporator during the freezing period at a lower temperature thanin the old system. The gas from the condenser compressed in thecompressor is admitted to the shell 2 with ample pressure to evacuatethe liquid refrigerant from said shell. and at comparatively hightemperature to effect rapid thawing of the adherent ice surfaces.

At the conclusion of the evacuation period the positions of the severalvalves are restored to those proper for the functioning of thesucceeding freezing phase of the refrigeration cycle.

By the above operation, the evaporator pressure is raised to effect theliquid evacuation and release of the loci a high vacuum on thecompressor is avoided; and the compressor does useful refrigerating workin cooling the liquid in the condenser and-receiver.

In Figure 1 the valves 6, I1, 20, 2| and 23 are each shown as solenoidoperated, and may be actuated through a motor driven controller 24having cams 25, which at proper intervals trip mercoid switches 26 incircuit with the respective solenoid valves.

In that form of the invention shown in Figure 3, the valves 2| and 23 ofFigure 1 are substituted by a three-Way diaphragm valve 21 operatingremotely respective to pressure variation in the conduit between thecondenser and evaporator inherent to the equalization of pressurebetween these vessels at one time, and the restoral of compressorpressure at another. Pressure control of the three-way valve 21 iseffected through the intermediary of a pressure actuated switch and a.three-way magnetic valve operated through said switch, and italternately applies pressure to the diaphragm of the valve 21 andreleases pressure from said diaphragm,

The three-way valve 21 has a valve member 28 with stem 29 connected to adiaphragm 30 within a casing 3i forming a diaphragm chamber. The valvemember 28 has alternate seating positions determined by the position orthe diaphragm. In its lower seating position it opens the avenue ofcommunication between the high side of the compressor and the condenser,functioning as valve 2| in Figure 1. In its upper seating position itopens a passage between the condenser and suction Side of thecompressor, therefore functioning as valve 23 in Figure 1. The valvemember 28 moves all the way from one seating position to the other, sothat when one passage is open, the other is closed. It is normallybiased to its lower seat by a spring 40, so that the upper valve passageis normally open. The valve 21 is actuated by a pressure responsiveswitch 32, the motor element of which is in communication with theconduit 8, in which the pressure falls when the valve I7 is opened, toequalize the pressure between the condenser and evaporator, and in whichthe pressure rises when the valve I1 is closed. The switch 32 closeswhen pressure in conduit It falls, engaging the solenoid 33 of thethree-way magnetic valve 34. This valve has a pipe 35 communicating withthe diaphragm chamber of the valve 27, which pipe is alternatelyconnected to the high pressure conduit 36 or to a relief conduit 31communicating with the suction conduit 5. The solenoid, when energized,rocks a lever 38, moving the valve member 39 upward to admit highpressure to the diaphragm chamber.

Figure 4 represents a conventionalized diagram of the salient featuresof the system illustrating the broad concept of the invention. In thisview the condenser and evaporator are connected by a low pressureconduit p and a high pressure conduit q. The low side of the compressoris connected at an intermediate point to the low pressure conduit, andthe high side of the compressor at an intermediate point to the highpressure conduit. The low pressure conduit 12 is provided with theevaporator low pressure valve A and the condenser low pressure valve onopposite sides of the point of connection of said conduit with thecompressor, the valve A serving the evaporator and the valve C, thecondenser. The evaporator high pressure valve D and the condenser highpressure valve B are intercalated in the pressure conduit on oppositesides of the point of connection of the compressor with said conduit.the valve D serving the evaporator and the valve B, the condenser. Thedisplacement reservoir is connected by a relief conduit 1' with thesuction conduit at a point between the valve A and a compressorconnection. A relief valve E is in the relief conduit. Normally, forperforming a freezing cycle in the evaporator, the valves of the systemare so set that the valve A is open, the valve C closed, the valve Dclosed, and the valve B open. When it is desired to reverse thefunctions of the compressor so as to perform a suction cycle in thecondenser and to deliver hot compressed gas to the evaporator, thepositions of the valves are reversed. The valve A is closed and thevalve C is opened. The valve D is opened and the valve B closed. IHowevc'r, in practice, it is found desirable to have the "ndividualvalves open and close in a certain sequence. The valves A and D arefirst operated, being simultaneously respectively closed and opened. Therelief valve E may be opened at the same time as the valve D. The valveB is then closed a few seconds after the opening of the valve D, whilethe valve C may be Opened simultaneously with the closing of valve Thissequence of operation permits the compressor to evacuate thedisplacement chamber immediately following the closing or the valve Aand prior to the opening of the valve 0. It also permits the condenserpressure to equalize with the evaporator pressure while the valves B andD are open. This lowers the pressure in the condenser and prevents thecompressor from having to compress the already highly compressed gasfrom the condenser and which might produce an excessive compressionpressure,

While I have in the above disclosure described what I believe to bepreferred and practical embodiments of the invention. it will beunderstood to those skilled in the art that the specific arrangement ofparts and sequence in the operation of the valves as well as thespecific means by which the valves are operated are by way ofillustration and not to be construed as restricting the scope of theinvention which is defined in the appended claims.

What I claim as my invention is:

1. In a system for freezing fee, a condenser, an evaporator, a vessel insaid evaporator in which ice is frozen and from the surface of which itis thawed following freezing by replacement of liquid refrigerant insaid evaporator by hot gaseous refrigerant under pressure, adisplacement vessel connected to said evaporator into which the liquidrefrigerant is evacuated, a compressor, conduits between said compressorand said condenser and evaporator, a conduit between said displacementvessel and the suction side of said compressor, valve means controllingsaid conduits, means for periodically operating said valve means tocause said compressor alternately to pump from said evaporator to saidcondenser and from said condenser to said evaporator, definingsuccessive freezing and evacuation phases, and to open said displacementchamber conduit to the suction side of the compressor at the beginningof the evacuation phase and close it at the beginning of the freezingphase.

2. In a system for freezing ice, a condenser, an evaporator and acompressor operatively connected to said condenser and evaporator, avessel in said evaporator in which ice is frozen and from the surface ofwhich it is thawed following freezing by replacement of liquidrefrigerant by hot gaseous refrigerant under pressure, means forperiodically reversing the external functions of the compressor wherebyit alternately pumps from the evaporator into the condenser and from thecom denser into the evaporator. and means for equalizing the pressurebetween the condenser and evaporator immediately prior to the pumpingfrom the condenser to the evaporator.

3. In a system for freezing ice, an evaporator and a condenser unit,there being a liquid refrigerant conduit from said condenser unit tosaid evaporator, a vessel in said evaporator in which ice is frozen andfrom the surface of which the ice is thawed following freezing, agaseous refrigerant conduit communicating with said condenser unit, lowand high pressure branch conduits communicating with said gaseousrefrigerant conduit and with said evaporator, a compressor having itsinduction side connected to said low pressure branch at an intermediatepoint and having its eduction side connected at an intermediate point tosaid high pressure branch, an evaporator suction valve in said lowpressure branch and an evaporator pressure valve in said high pressurebranch, both of said valves being between the evaporator and thecompressor, means for substantially simultaneou-sly operating saidvalves to close one and open the other, a fluid pressure responsivethreeway valve intercalated in said system between said compressor andcondenser having a port communicating with said low pressure branch, aport communicating with said high pressure branch and a portcommunicating with said gaseous refrigerant conduit, including valvemeans for placing said low and high pressure ports alternately incommunication with said gaseous refrigerant conduit port, a diaphragmfor actuating said valve means, a magnetic valve for alternatelysubjecting said diaphragm to diflerential pressures derived from therespective low and high pressure branches, a pressure actuated switchfor operating said magnetic valve having a pressure elementcommunicating with said low pressure branch, responsive to pressurevalves therein incident to the opening and closing of the evaporatorpressure valve, the high and low pressure ports of said three-way valvebeing normally respectively open and closed when the evaporator suctionand pressure valves are respectively open and closed.

4. In a system 'for freezing ice, an evaporator and a con-denser unit,there being a liquid refrigerant conduit from said condenser unit tosaid evaporator, a vessel in said evaporator in which ice is frozen andfrom the surface of which ice is thawed following freezing, adisplacement reservoir for liquid refrigerant connected to the lowerpart of said evaporator, a gaseous refrigerant conduit communicatingwith said condenser unit, high and low pressure branch conduitscommunicating with said gaseous refrigerant conduit and with saidevaporator, a compressor having its induction side connected to said lowpressure branch and its eduction side connected to said high pressurebranch, valves in said high pressure branch on opposite sides of thepoint of connection of said compressor with said branch, respectivelyalternately opened and closed to selectively direct compressed gaseousrefrigerant to said condenser unit or to said evaporator, valves in saidlow pressure branch on opposite sides of the point of connection of saidcompressor with said branch, respectively alternately opened and closedto selectively draw gaseous refrigerant from said evaporator orcondenser, and means for opening and closing the said valves in eachbranch conduit in alternation, and with respect to both branch conduits,operating said valves which are on corresponding sides of the compressorconnections, in opposite phase.

5. In a system for freezing ice, an evaporator and a condenser unit,there being a liquid refrigerant conduit from said condenser unit tosaid evaporator, a vessel in said evaporator in which ice is frozen andfrom the surface of which the ice is thawed following freezing, agaseous refrigerant conduit communicating with said condenser unit, highand low pressure branch conduits communicating with said gaseousrefrigerant conduit and with said evaporator, a compressor having itsinduction side connected to said low pressure branch and its eductionside connected to said high pressure branch, valves in said highpressure branch on opposite sides of the point of connection of saidcompressor with said branch, respectively alternately opened and closedto selectively direct compressed gaseous refrigerant to said condenserunit or to said evaporator, valves in said low pressure branch onopposite sides of the point of connection of said compressor with saidbranch, respectively alternately opened and closed to selectively drawgaseous refrigerant from said evaporator or condenser, one of said lastnamed valves being ad- ,iacent said evaporator, a displacement reservoirfor liquid refrigerant connected to the lower part of said evaporator, arelief conduit establishing communication between the upper part of saidreservoir and said low pressure branch at a point between the compressorconnection with said branch and said adjacent valve, a valve in saidrelief conduit, and means for opening and closing the said valves ineach branch conduit in alternation, and with respect to both branchconduits, operatingsaid valves which are on op posite sides of thecompressor connections, in opposite phase, and means for opening andclosing the valve in said relief conduit in phase with said adjacentvalve.

6. In a system for freezing ice which includes a compressor, condenser,evaporator and a vessel in which ice is frozen, inheat exchangingrelation to said evaporator, a liquid refrigerant displacement chamberconnected to the lower part of said evaporator, a liquid refrigerantconduit and a gaseous refrigerant conduit between said condenser andevaporator, said compressor being intercalated in said gaseousrefrigerant conduit, said evaporator and displacement chamber beingconnected in parallel to said gaseous refrigerant conduit on the sameside of said compressor, the

,latter functioning normally to suck from said evaporator and deliverunder pressure to said condenser producing refrigeration in saidevaporator, the method of operating such a system to change the freezingphase to a thawing phase in said evaporator, comprising substantiallysimultaneously cutting off the suction of said compressor from saidevaporator and putting said displacement chamber into communication withthe suction side of said compressor to exhaust said displacementchamber, then reversing the functions of the compressor by causing it tosuck from said condenser and deliver hot gaseous refrigerant underpressure to said evaporator, thereby displacing the liquid refrigeranttherein into the exhausted displacement chamber, and bringing said hotgaseous refrigerant into heat exchanging relation to said vessel.

7. In a system for freezing ice which includes a compressor, condenser,evaporator and a vessel in which ice is frozen, in heat exchangingrelation to said evaporator, a liquid refrigerant displacement chamberconnected to the lower part of said evaporator, a liquid refrigerantconduit and a gaseous refrigerant conduit between said condenser andevaporator, said compressor being intercalated in said gaseousrefrigerant conduit, said evaporator and displacement chamber beingconnected in parallel to said gaseous refrigerant conduit on the sameside of said compressor, the latter functioning normally to suck fromsaid evaporator and deliver under pressure to said condenser producingrefrigeration in said evaporator, the method of operating such a systemto change the freezing phase to a thawing phase in said evaporator,comprising substantially simultaneously cutting off the suction of saidcompressor from said evaporator, putting said condenser into directcommunication with said evaporator by-passing said compressor, andputting said displacement chamber into communication with the suctionside of said compressor to exhaust said displacement chamber, thenreversing the functions of the compressor by causing it to suck fromsaid condenser and to deliver hot gaseous refrlgerant under pressure tosaid evaporator, thereby displacing the liquid refrigerant th'erein intothe exhausted displacement chamber, and bringing hot gaseous refrigerantinto heat exchanging relation to said vessel.

8. In a system for freezing ice in which the normal freezing phase isfollowed by a thawing phase, a compressor, condenser, evaporator, and avessel in which ice is frozen in heat exchanging relation to saidevaporator, a liquid refrigerant displacement chamber connected to thelower part of said evaporator, a liquid refrigerant conduit and agaseous refrigerant conduit between said condenser and evaporator, saidcompressor being intercalated in said gaseous refrigerant conduit, saidgaseous refrigerant conduit including a branch conduit to saidevaporator by-passing said compressor, said evaporator and displacementchamber being connected in parallel to said gaseous refrigerant conduiton the same side of said compressor, the latter functioning normally tosuck from said evaporator and deliver under pressure to said condenserproducing refrigeration in said evaporator, means operating followingthe freezing phase for substantially simultaneously cutting off thesuction of said compressor from said evaporator and putting saiddisplacement chamber into communication with the suction side of saidcompressor to exhaust said displacement chamber, and means operatingsequentially to said first named means for reversing the functions ofsaid compressor causing it to suck gaseous refrigerant from thecondenser and to deliver hot gaseous refrigerant under pressure to saidevaporator, thereby displacing the'liquid refrigerant therein into theexhausted displacement chamber and bringing said hot gaseous refrigerantinto heat exchanging relation to said vessel.

9. In a system for freezing ice in which the normal freezing phase isfollowed by a thawing phase, a compressor, condenser, evaporator, and avessel in which ice is frozen in heat exchanging relation to saidevaporator, a liquid refrigerant displacement chamber connected to thelower part of said evaporator, a liquid refrigerant conduit and agaseous refrigerant conduit between said condenser and evaporator, saidcompressor being intercalated in said gaseous refrigerant conduit, saidgaseous refrigerant conduit including a branch conduit to saidevaporator bypassing said compressor, said evaporator and displacementchamber being connected in parallel to said gaseous refrigerant conduiton the same side of said compressor, the latter functioning normally tosuck-from said evaporator and to deliver under pressure to saidcondenser producing refrigeration in said evaporator, means operatingfollowing the freezing phase for substantially simultaneously cuttingoff the suction of said compressor from said evaporator, putting saiddisplacement chamber into communication with the suction side of saidcompressor to exhaust said displacement chamber, and putting saidcondenser into direct communication with said evaporator, and meansoperating sequential to said first named means for reversing thefunctions of said compressor to cause it to suck gaseous refrigerantfrom said condenser and to deliver hot gaseous refrigerant underpressure to said evaporato r thereby displacing the liquid refrigeranttherein into the exhausted displacement chamber and bringing said hotgaseous refrigerant into heat exchanging relation to said vessel.

BENJAMIN F. KUBAUGH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,135,285 Gibson Nov. 1, 19382,182,691 Crago Dec. 5, 1939 2,221,212 Wussow et al Nov. 12, 1940 4,01Wussow et a1 Nov. 28, 1944

